The present invention relates to a measuring method and apparatus for providing a record of environmental factors to which a product is exposed during a manufacturing process or the like and particularly to such a method and apparatus for generating substantially continuous data.
Manufacturing processes are designed to operate in a predetermined manner wherein environmental factors, especially those which may be critical to the process, are controlled within acceptable tolerances. Depending upon the process, it may be desirable to control pressure, radiation, vibration, temperature, humidity, pH or other parameters to which a product is exposed. Although it is possible to monitor these factors with instruments positioned at various stages in the process, the actual parameters to which a manufactured product is subjected at other stages may be relatively unknown because of harsh environmental conditions or inconvenience of probing those areas. For example, some manufacturing processes involve extremes in temperature, acidity, alkalinity, and the like where the interposition of test leads is difficult or impractical. In any case, it is not generally feasible to explore multiple parameters at every stage along a manufacturing process even in the absence of extremes. Rather, the data is discontinuous, containing gaps, wherein data, if it were available, might have revealed unacceptable conditions potentially resulting in a flawed or even dangerous end product.